Study on Disease Mechanism and Theoretical Quantification Method of Tunnel Structure

Table 3

Evaluation criteria for the development of cracks.

Crack width b (mm)		Crack length l (m)		Rating status
b > 3	b ≤ 3	l > 5	l ≤ 5
✓		✓		3/4
✓			✓	2/3
	✓	✓		2
	✓		✓	2